pH is the hydrogen ion concentration and pOH is the hydroxide ion concentration in the solution. pH KOH is 12.73, pOH KOH is 2.24 and pH NaCl is 7.
<h3>What are pH and pOH?</h3>
pH is the negative log of the hydrogen ion concentration and pOH is the negative log of the hydroxide ion concentration.
The relation between the pH and pOH can be given as, 
The pH of KOH can be calculated by the formula,
![\rm pH = \rm -log [H^{+}]](https://tex.z-dn.net/?f=%5Crm%20pH%20%3D%20%5Crm%20-log%20%5BH%5E%7B%2B%7D%5D)
In the first case, the concentration of the KOH is 
Substituting values in the equation:
![\begin{aligned} \rm pH &= \rm -log [H^{+}]\\\\&= \rm -log [1. 87 \times 10^{-13}\;\rm M ]\\\\&= 12.73\end{aligned}](https://tex.z-dn.net/?f=%5Cbegin%7Baligned%7D%20%5Crm%20pH%20%26%3D%20%5Crm%20-log%20%5BH%5E%7B%2B%7D%5D%5C%5C%5C%5C%26%3D%20%5Crm%20-log%20%5B1.%2087%20%5Ctimes%20%2010%5E%7B-13%7D%5C%3B%5Crm%20%20M%20%5D%5C%5C%5C%5C%26%3D%2012.73%5Cend%7Baligned%7D)
Hence, the pH of KOH is 12.73.
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pOH of KOH can be calculated by the formula,
![\rm pOH = \rm -log [OH^{-}]](https://tex.z-dn.net/?f=%5Crm%20pOH%20%3D%20%5Crm%20-log%20%5BOH%5E%7B-%7D%5D)
The hydroxide concentration of the KOH solution is 
Substituting value in the equation:
![\begin{aligned} \rm pOH &= \rm -log [OH^{-}]\\\\&= \rm -log [5. 81 \times 10^{-3}\;\rm M ]\\\\&= 2.24 \end{aligned}](https://tex.z-dn.net/?f=%5Cbegin%7Baligned%7D%20%5Crm%20pOH%20%26%3D%20%5Crm%20-log%20%5BOH%5E%7B-%7D%5D%5C%5C%5C%5C%26%3D%20%5Crm%20-log%20%5B5.%2081%20%5Ctimes%2010%5E%7B-3%7D%5C%3B%5Crm%20%20M%20%5D%5C%5C%5C%5C%26%3D%202.24%20%5Cend%7Baligned%7D)
Hence, the pOH of KOH is 2.24
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The pH of NaCl can be calculated by the formula,
![\rm pH = \rm -log [H^{+}]](https://tex.z-dn.net/?f=%5Crm%20pH%20%3D%20%5Crm%20-log%20%5BH%5E%7B%2B%7D%5D)
In the third case, the concentration of the NaCl is 
Substituting values in the equation:
![\begin{aligned} \rm pH &= \rm -log [H^{+}]\\\\&= \rm -log [1. 00 \times 10^{-7}\;\rm M ]\\\\&= 7 \end{aligned}](https://tex.z-dn.net/?f=%5Cbegin%7Baligned%7D%20%5Crm%20pH%20%26%3D%20%5Crm%20-log%20%5BH%5E%7B%2B%7D%5D%5C%5C%5C%5C%26%3D%20%5Crm%20-log%20%5B1.%2000%20%5Ctimes%20%2010%5E%7B-7%7D%5C%3B%5Crm%20%20M%20%5D%5C%5C%5C%5C%26%3D%207%20%5Cend%7Baligned%7D)
Hence, the pH of KOH is 7.0.
Therefore, KOH is basic and NaCl is approximately neutral.
Learn more about pH and pOH here:
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